The study aims to establish an internationally accepted definition for child overweight and obesity, specifying measurement methods, reference populations, and age- and sex-specific cutoff points. An international survey of six large, nationally representative cross-sectional growth studies from Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States was conducted. The study used body mass index (BMI) as the main outcome measure. Centile curves were drawn for each study, with curves at age 18 passing through the widely used adult cutoff points of 25 and 30 kg/m² for overweight and obesity. These curves were averaged to provide age- and sex-specific cutoff points for children aged 2-18 years. The proposed cutoff points are less arbitrary and more internationally based than current alternatives, and should help provide internationally comparable prevalence rates of overweight and obesity in children. The study found that the adult cutoff points of 25 and 30 kg/m² for overweight and obesity, respectively, are related to health risk and are convenient round numbers. The study used these adult cutoff points to link to BMI centiles for children to provide child cutoff points. The study used the LMS method to construct centile curves for BMI in each dataset. The curves were then averaged to provide a single smooth curve passing through the adult cutoff points. The resulting curves were used to define cutoff points for overweight and obesity in children. The study found that the curves were reasonably consistent across countries between ages 8 and 18, although there were some variations. The study also found that the cutoff points for Singapore were higher between ages 10 and 15, which may be due to increased median BMI and greater variability. The study concluded that the proposed cutoff points, based on international data and linked to the widely accepted adult cutoff points of 25 and 30 kg/m², should help provide internationally comparable prevalence rates of overweight and obesity in children. The study also noted that the cutoff points are less arbitrary and more internationally based than current alternatives. The study recommends the use of these cutoff points for international comparisons of prevalence of overweight and obesity.The study aims to establish an internationally accepted definition for child overweight and obesity, specifying measurement methods, reference populations, and age- and sex-specific cutoff points. An international survey of six large, nationally representative cross-sectional growth studies from Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States was conducted. The study used body mass index (BMI) as the main outcome measure. Centile curves were drawn for each study, with curves at age 18 passing through the widely used adult cutoff points of 25 and 30 kg/m² for overweight and obesity. These curves were averaged to provide age- and sex-specific cutoff points for children aged 2-18 years. The proposed cutoff points are less arbitrary and more internationally based than current alternatives, and should help provide internationally comparable prevalence rates of overweight and obesity in children. The study found that the adult cutoff points of 25 and 30 kg/m² for overweight and obesity, respectively, are related to health risk and are convenient round numbers. The study used these adult cutoff points to link to BMI centiles for children to provide child cutoff points. The study used the LMS method to construct centile curves for BMI in each dataset. The curves were then averaged to provide a single smooth curve passing through the adult cutoff points. The resulting curves were used to define cutoff points for overweight and obesity in children. The study found that the curves were reasonably consistent across countries between ages 8 and 18, although there were some variations. The study also found that the cutoff points for Singapore were higher between ages 10 and 15, which may be due to increased median BMI and greater variability. The study concluded that the proposed cutoff points, based on international data and linked to the widely accepted adult cutoff points of 25 and 30 kg/m², should help provide internationally comparable prevalence rates of overweight and obesity in children. The study also noted that the cutoff points are less arbitrary and more internationally based than current alternatives. The study recommends the use of these cutoff points for international comparisons of prevalence of overweight and obesity.